Maths Skills for Chemistry (~20% of Marks)

Approximately 20% of the marks on each Edexcel GCSE Chemistry paper require mathematical skills. Across both papers, that is roughly 40 marks — enough to make the difference of several grades. This lesson covers every maths skill you need, with worked examples specific to Chemistry.

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The Maths Skills Tested

The Edexcel specification lists the following mathematical requirements:

Skill	Where It Appears in Chemistry
Arithmetic and numerical computation	Calculating Mr, moles, percentages
Handling data	Mean, range, identifying anomalies
Algebra	Rearranging formulae, substitution
Graphs	Plotting, reading values, calculating gradients
Geometry and measures	Unit conversions
Statistics	Mean calculations, understanding uncertainty

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Calculating Relative Formula Mass (Mr)

This is the foundation of almost every Chemistry calculation. You will use Mr in moles, concentration, percentage yield, and atom economy questions.